All terrain vehicles (ATV's) have been known for many years. They comprise an engine and transmission used to propel the vehicle over rough terrain. The engine generally comprises a two stroke or four stroke arrangement with a transmission attached. The transmission is generally similar those used on motorcycles, particularly since the engines are also usually derived from motorcycles.
One drawback for ATV's is the ability to back the vehicle should the need arise. Transmissions are available for this function, however, they can be costly, bulky and complex. Complexity can adversely affect performance and reliability since component failure is often related to the number of moving parts. The size of the reversing transmission can be a limiting factor in vehicle design as well. A large, heavy transmission is not desirable when total vehicle weight is in the range of only 400-500 pounds.
U.S. Pat. No. 6,742,618 (2004) which discloses a reduction drive system including planetary gears. In an alternate embodiment, a reversing unit is provided.
What is needed is a reverse sprocket transfer case having a moveable cam member selectively engagable with a planetary gear portion, whereby the rotation of the planetary gear portion is stopped when the cam member is engaged with the planetary gear portion. The present invention meets this need.